The control device of induction motors in electric vehicles is one of the important parts of electric vehicles. Its main use is to maximize the output efficiency of induction motor by operating the electric vehicle according to the determined direction, speed, angle and reaction time. Because induction motors have advantages such as low cost, high stability, high speed, low torque fluctuation/noise and position sensor-less, they are now widely adopted as induction motors which are most suitable for electric vehicles. However, when the induction motor is operated in a medium and low load state, copper loss and iron loss increase due to an increase in the reactive power of the induction motor, and the operation efficiency and the power factor of the induction motor decrease greatly, which causes a big problem including the occurrence of severe and wasteful power consumption. In the case of an electric vehicle, the use time and travel distance of the charged battery are significantly shortened.
According to the present invention, when the total load of the induction motor of the electric vehicle greatly changes, the variation of the load factor and the rotation speed can be detected in real time, and the input power of the induction motor can be adapted to the total load of the electric vehicle at all times. If the total load of the electric vehicle is less than the input power of the induction motor, the input power of the induction motor is automatically adjusted to a minimum value; when the maximum load of the electric vehicle is reached, the input electric power of the induction motor of the electric vehicle is automatically adjusted to a maximum value, according to an efficiency optimizing method and a control device, and the main role of which is to improve output efficiency of the induction motor through the control of the relevant parameters of the induction motor.